American Society of Hirudotherapy

Low genetic diversity in Ozobranchus jantseanus in Japan: possibility of introduction with their host turtles

Population genetics published in Parasitology International (2017)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Safety & Infection ControlNakano T et al. · Parasitology international, 2017

Abstract

Leeches belonging to the genus Ozobranchus are ectoparasitic on sea and freshwater turtles. The freshwater species O. jantseanus has been recorded from China and Japan. Ozobranchus jantseanus inhabiting Japan is considered to be a non-indigenous species, because their primary host, the Reeves' pond turtle, Mauremys reevesii, is thought to have been introduced in the last few centuries from adjacent Asian countries. To assess whether the Japanese populations of O. jantseanus were likely to have been introduced, their genetic diversity was investigated using mitochondrial cytochrome c oxidase subunit I sequences. The very low sequence diversity as well as the historical record of this species from Japan suggest that Japanese populations of O. jantseanus may have been artificially introduced along with their host turtles. Molecular phylogenies of COI showed that two marine Ozobranchus species formed a clade together with the freshwater O. jantseanus.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal Article
Indexed MeSH termsAnimalsDNA, MitochondrialElectron Transport Complex IVGenetic VariationHost-Parasite InteractionsIntroduced SpeciesJapanLeechesPhylogenyTurtles

Summary

Low genetic diversity of O. jantseanus in Japan suggests introduction with host Mauremys reevesii turtles — implications for invasive leech surveillance.

Why This Matters for Hirudotherapy

This study investigated genetic diversity of the freshwater turtle leech Ozobranchus jantseanus in Japan using mitochondrial cytochrome c oxidase subunit I (COI) sequences. Very low sequence diversity, combined with historical records, suggested Japanese populations may have been artificially introduced along with their host, the Reeves' pond turtle (Mauremys reevesii). Phylogenetic analysis showed two marine Ozobranchus species formed a clade with freshwater O. jantseanus. This is a phylogeographic and population genetics study of a turtle ectoparasite. It has no relevance to medicinal hirudotherapy or the therapeutic leech secretome.

Citation

Low genetic diversity in Ozobranchus jantseanus in Japan: possibility of introduction with their host turtles.

Nakano T et al. · Parasitology international, 2017

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